This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Our lab has recently identified a novel stem cell paracrine factor secreted by mesenchymal stem cells overexpressing Akt that reduces apoptosis of cardiomyocytes exposed to hypoxia. We have generated a heart specific transgenic mouse line to overexpress this factor under the control of the cardiac alpha-myosin heavy chain promoter. The specific aim of proposed study is to assess myocardial infarct size and cardiac function 24 hours post acute coronary ligation using Gadolinium (Gd) hyperconstrast cardiac gated MRI in wild type and alphaMHC-HASF transgenic mice. This would represent a pilot study in which we would compare our current methodologies to MRI to use in long-term, multiple scan (days 14 and 30 post-infarction) assessment of cardiac remodeling in these transgenic mice. Current modalities utilized by our lab to assess myocardial infarct size are dependent on 2,3,5-triphenyl tetrazolium chloride (TTC) and Evan's Blue staining to delineate the area at risk and infarct area. This method requires euthanizing the animals and harvesting tissue. Cardiac function has been assessed by echocardiogram. Gd-hyperconstrast cardiac gated MRI has been shown to be accurate at measuring in vivo infarct size without the need to sacrifice the animal. In addition, cardiac function parameters including ejection fraction (EF), end-diastolic and end-systolic dimensions and volumes, and wall thickness can be evaluated. The major advantage of MRI allows for infarct area and cardiac remodeling parameters to be measured at multiple time-points in the same animal, which reduces the number of animals need and increase the accuracy of data collected.